1. Field of the Invention
The present invention relates to air pumps. More specifically, the present invention relates to methods and apparatus for an electric air pump having multiple parallel impellers mounted upon the same motor shaft for increasing the dissipation of heat from an electric motor in the pump and the efficiency of delivering low pressure, high volume air as desired to, for example, an inflatable device, or in the alternative, exhausting air from an inflated device.
2. Description of the Prior Art
The prior art is directed to methods and apparatus for electrically driven pumps having a rotating impeller or fan with a plurality of blades for moving fluids or gases typically in compressors, pumps, electrical appliances, and the like.
All alternating current (AC) and direct current (DC) electrical air pumps and some electrical appliances such as, for example, hair dryers utilize a fan blade or an air impeller to gather and subsequently force air through an opening known as an exhaust port. The movement of the air through the exhaust port results in achieving the desired goal of, for example, inflating a product in the case of an inflatable device or creating a stream of forced air to dry the hair in the case of a hair dryer.
Nominally, there are three types of electric air pumps. They include (a) low pressure, high volume pumps that are typically used to inflate toys, air mattresses and other inflatable devices, (b) high pressure, low-to-medium air volume pumps that are employed to inflate bicycle tires and sports equipment such as basketballs, footballs, volleyballs and the like, and (c) high pressure, high volume pumps generally referred to as air compressors that employ a pressure chamber for inflating such items as automobile tires or for use in construction projects. Each of these conventional types of electric air pumps typically include a motor that drives a single fan blade or impeller at a fixed number of revolutions per minute (RPM) and is useful in inflating products.
Many examples of electrical driven pumps are known in the prior art. A first example is directed to a double impeller wheel for axial flow fans comprising a set of inner impeller blades surrounded by an intermediate ring, a set of outer impeller blades secured to the ring, where the width of the ring in the axial direction is less than that of the impeller blades. The first example teaches a non-parallel double impeller blade mounted on a single shaft. In a second example, a fluid flow detector member for a rotor blade typically found in a gas turbine projects outwardly from the radially outer end of the blade into a region of leakage fluid flow. An exchange of momentum occurs between the flow of the leakage fluid and the detector surface. The detector member thus transmits a force to the blade acting in the direction of blade rotation. The second example teaches multiple parallel impellers mounted upon a common rotating shaft. A third example teaches a flow control mechanism for compressors and pumps having a vane equipped guide element disposed in a fluid compressor or pump between the usual impeller and the fluid flow inlet. A flow control means includes a rotary guide member fixed on one end of a shaft supported for rotation in a bearing at the outer end of and in alignment with the axis of the impeller. The guide member includes a hub and radially outward projecting blades.
A fourth example teaches an open vane regenerative impeller for a submerged fuel pump wherein the impeller has a ring-like body portion for which a plurality of open-vane impeller vanes extend radially outward and a plurality of fan blades extend radially inward. A final example teaches an electrically driven air pump for a motor vehicle for pumping secondary air into the exhaust gas system to improve the properties of the exhaust gases. The air pump includes a housing, a pump mechanism in the housing, and an electric motor in the housing connected in driving relation to the pump mechanism. An air passage in the housing provides a flow of air past the electric motor to the pumping mechanism. The air passage includes a suction nozzle for supplying air to an inlet collar of a pump impeller of a pump mechanism. The suction nozzle projects into the collar to supply air from the electric motor to the pump mechanism. A single impeller is shown attached to a motor shaft.
Thus, there is a need in the art for an electric air pump having multiple impellers which are parallel mounted on the same motor shaft where the multiple impellers provide improved motor efficiency in heat dissipation and air volume delivery when compared to a single impeller motor operating at the same RPM, and where the multiple parallel mounted impellers exhibit dimensions sufficiently exact so that a near zero True Indicator Reading (TIR) can be accomplished by manual assembly of the components of the motor.